Analysis and control for a new reconfigurable parallel mechanism

Huang, Guoquan; Zhang, Dan; Tang, Hongyan; Kong, Lingyu; Song, Sumian

doi:10.1177/1729881420931322

Cited by 9 publications

(6 citation statements)

References 47 publications

(59 reference statements)

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“…The Jacobian matrix of velocity for the sixth structure state is 3 J and the matrix of the Hookean Spring constants of the kinematic pairs of the mechanism in the sixth structure state is described in equation ( 12). The flexibility matrix of the sixth structure state is shown in equation (13).…”

Section: Flexibility Matrix Analysis Of Structural State Stiffness Of...mentioning

confidence: 99%

“…Although multitasking timber harvesters operating in timber production areas have been upgraded in recent years, the innovative designing method for and theoretical research on timber production machinery still remains weak [12][13][14][15][16][17]. In this paper, the methods from modern mechanisms that create reconfigurable mechanisms are applied to the design of the logging and brand-lopping mechanism which present a novel logging and branch-lopping mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Design and Analyses of a Novel Reconfigurable Logging Branch Mechanism

Shi,

Peng,

Liao

2024

J. Phys.: Conf. Ser.

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A reconfigurable logging and branch-lopping mechanism has been designed to shorten the production cycle, reduce work intensity, and improve labor survival rate in the logging industry. The mechanism integrating logging and branch-lopping functions can flexibly morph into three con-figurations, namely, series, parallel and mixed, as well as eight structure states to satiate different requirements. Not only does it possess sufficient stiffness to fell large trees but it also offers high flexibility to trim and crop small branches which superior performance has relatively wide engineering application prospects. The kinematics and static stiffness of the mechanism are the key techniques for its engineering application. With the mechanism as the research object, the working principles were analysed and the adjacency matrix of each structure state was presented. The Screw Theory and CGK formula were deployed to calculate the degrees of freedom of some of the structure mechanisms. The kinematics of some of the structure states was analysed and their flexibility matrices were obtained with vector algebra. The static stiffness of two structure states was compared indirectly by contrasting their flexibility matrices before their kinematics was simulated numerically. Engineering application of the mechanism in welding robots, robots that pick up objects, cleaning robots and other fields is demonstrated towards the end of this paper.

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Section: Flexibility Matrix Analysis Of Structural State Stiffness Of...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design and Analyses of a Novel Reconfigurable Logging Branch Mechanism

Shi,

Peng,

Liao

2024

J. Phys.: Conf. Ser.

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“…The related control problem is non-trivial, and several approaches require the transformation of the robot’s dynamic model into a form where the computation of the stabilizing control inputs is finally enabled (Le et al, 2013a; Lara-Molina et al, 2016; Lara-Molina et al, 2014; Le et al, 2011, 2013b). Indicative results on model-based and mode-free control of parallel robotic manipulators can be found in Harandi et al (2021), Xie et al (2021), Morlock et al (2021), Huang et al (2020), Jiang et al (2021). However, little has been done so far for the solution of the optimal control problem for the dynamic model of the five-link closed-chain robotic mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…Indicative results on model-based and mode-free control of parallel robotic manipulators can be found in Harandi et al (2021), Xie et al (2021), Morlock et al (2021), Huang et al (2020), Jiang et al (2021). However, little has been done so far for the solution of the optimal control problem for the dynamic model of the five-link closedchain robotic mechanism.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear optimal control for a five-link parallel robotic manipulator

Rigatos

Abbaszadeh

2022

Journal of Vibration and Control

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Control and stabilization of parallel robotic manipulators is a non-trivial problem because of nonlinearities and the multi-variable structure. In this article, a nonlinear optimal control approach is proposed for the dynamic model of such robotic systems, using as a case-study the model of a five-link parallel robot. The dynamic model of the parallel robotic manipulator undergoes approximate linearization around a temporary operating point that is recomputed at each time-step of the control method. The linearization relies on Taylor series expansion and on the associated Jacobian matrices. For the linearized state-space model of the system, a stabilizing optimal (H-infinity) feedback controller is designed. This controller stands as a solution to the nonlinear optimal control problem under model uncertainty and external perturbations. To compute the controller’s feedback gains, an algebraic Riccati equation is repetitively solved at each iteration of the control algorithm. The stability properties of the control method are proven through Lyapunov analysis. Finally, to implement state estimation-based control without the need to measure the entire state vector of the parallel robotic manipulator, the H-infinity Kalman filter is used as a robust state estimator. Among the advantages of this control method, one can note that (i) unlike the popular computed-torque method for robotic manipulators, the new control approach is characterized by optimality and is also applicable when the number of control inputs is not equal to the robot’s number of DOFs and (ii) it achieves fast and accurate tracking of reference set points under minimal energy consumption by the robot’s actuators.

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“…As the foundation of error compensation, it is a key issue to establish the correct compensation model. A number of methods or techniques on error modeling are designed in past years, such as HTM, multi-body system (MBS) theory [11,12], rigid body kinematics [13], screw theory [14][15][16], sequential decoupling compensation method [17], etc. HTM is a popular modeling method, and plenty of papers presented the HTM techniques for CNC machines compensation with HTM.…”

Section: Introductionmentioning

confidence: 99%

Modeling of CNC machine tools’ spatial geometric error based on two-dimensional angle error

et al. 2022

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A modeling method of CNC machine tools’ spatial geometric error is proposed based on two-dimensional angle error in this paper. Different from traditional modeling method, this method takes into account the effect of additional angle errors because the machine tool’s angle errors in the system of the lower guide rail will be passed on to slip board structure to the upper guide rail system. Firstly, after analyzing the principle of two-dimensional angle error, an optimized error compensation model of CNC machine tools’ spatial geometric error contains two-dimensional angle error is established through the traditional homogeneous coordinate transformation matrix method (HTM). Further, by applying the experiment, the compensation effect of the model is verified through comparing the body diagonal errors of CNC machine tools before and after compensation. Experiment results show that the body-diagonal accuracy after compensation based on the optimized model is 87.73% higher than that before compensation, and 54.82% higher than that of the traditional model after compensation. Article Highlights The highlight of the study reported here is threefold: Firstly, the principle of two-dimensional angle error is analyzed. Secondly, an optimized spatial geometric error compensation model of CNC machine tool is established based on the principle of two-dimensional angle error. Thirdly, the compensation effect of the optimized compensation model is verified by comparing the bodies diagonal precision of the machine tool.

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Analysis and control for a new reconfigurable parallel mechanism

Cited by 9 publications

References 47 publications

Design and Analyses of a Novel Reconfigurable Logging Branch Mechanism

Design and Analyses of a Novel Reconfigurable Logging Branch Mechanism

Nonlinear optimal control for a five-link parallel robotic manipulator

Modeling of CNC machine tools’ spatial geometric error based on two-dimensional angle error

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